SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9910ccc2c771427cd7033265a5a22a9255783334ab2be56cb4203e1f6758cc18' 
  AND token = 'sMD5JLKd3nPAyfLn79SNOS7D8Nv2PfBFO1xN3tt1TPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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