SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '705210a123351537a0776b426638081f16a29061d52eaed2e7ad002ce3f5e427' 
  AND token = 'juYoJvqkqS84r/xfLeTtU5yLuoN91mm/6pODFHqAr4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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