SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87231f969b602a9d641051b6bbbe224f025db650900cf7ac0f1a1b54c782f38d' 
  AND token = 'PKYKbpS3bAChsyTaUkn7nQ4NG2aJnrcRYL8DBCCcPY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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