SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b8786286fc51a63a0924dc104831eed345298a1a4e7cb996a81c94a86aedb34' 
  AND token = 'B1O4vWYryizMKSkZ3jpBywf4VRn251riJugnjl6hoUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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