SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '138c8eae09c98d0a45645029e68ed920ae6ed62fc037cff5d95841d44e1a6e4b' 
  AND token = 'EEwhwIZR1bmCWLHINqwSOdmh5n5uVEX8Vm1BDkPquQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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