SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '819d86bf9a40b0dc106bf6ce2a45343ac3ba779424f17aaffa9ddba6925ca05c' 
  AND token = 'F+9PxJv+XbHpDs4b9qzUkC76AKs12s+U9up3EJvlxm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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