SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aac65ca347310306a2c5465dfd19f1eb18566d26c4dbefac76b462fd74a3cbfe' 
  AND token = 'iAIIlTPSrMT+6GGFwUJNerLjGJ0I8n1ucuVmOOTSH3Q=' 
  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"
    }
  }
}