SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '50a49896b7ffb8ee6695c5d2fef53bcf2cf185816b1d361425785dc1454bc260' 
  AND token = '6ytE7R03dF2UzlR33sG4GEcgTUA3qkM1gbR8boxrqM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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