SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e118be6735b8d00f89c108d54fff1b45ba7472c9556e76eb2e1866003d84c78' 
  AND token = 'h+uNYC6uRS6dLl5KBok0x/vMOXrDOBCi8oIQDW19aMQ=' 
  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"
    }
  }
}