SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29cb576181f7c386a54dd12e054caaf3764c5d3295c645f2ab72ab3b1b6d7a9a' 
  AND token = 'k6rqkdwk62XuiklpDdUMo3G/qlnhHL+CPOUR9j47IK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}