SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95a0f1aa136bb927ec0cd880c4c45fcf2cee0ed3118ba42863f4eb1bd77892d8' 
  AND token = 'KltBUuxsZbJiZ4DI8ZLphdyQ1dHeGrBKjFA+I3RY6ZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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