SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a1c695826c177a3787da17acd8b598699bf5393603798567549f670e9bcae60' 
  AND token = 'MlQhFSzkpoGjWU7zhUQPhMBRO+4hTVHGoqxOLkEzC1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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