SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '371374c8bc8ee852d302cb40b032ffa0b7a16443908fce4696651dcbe0c0545f' 
  AND token = 'fvtKg0+dCxY139wz7GKNosCMpShrBGJuH3BliipcjNM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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