SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd2f6be7b036a9de592de091e735ca10315965d018c1e245100fab94fce561be' 
  AND token = 'TqdV0KpjfISeLHa6/U2GIVRndcnid5m2rBP//PC5Uz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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