SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc594602f0193a2b57b2c58137012c8462dd764393c1af5ca0db8c5072a627c3' 
  AND token = '1PpOERFZHkw+M7L66W9QFyZcBOQw76NujzLsVFcBNrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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