SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28fb00269b782f29edff18231d97bc611d46b72f69c6b94d85efae3d37230946' 
  AND token = 'i7nNfYDX7eq4On+LRolY6DNMMGMsnsngwCYLDDUARYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}