SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c398592bee65587188537613de3a6763f35c3e1cb526a3cdf8c8a1f90b9b51e3' 
  AND token = 'U7Ye3nob/deKIGSr65KkbHYFzV94QTEXmrDC2y0I5YM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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