SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc69c5fd4282dd9c99f4a0fb59adfd3055878c645f5332b983672be6ce3a9608' 
  AND token = 'cCrp1Q8i5gZfN+xNaZOpcPXjeN4nlsUusBLdbkffvWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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