SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '75faf872ca5a79f26e07b3227b9607986da4c44cc3b1b0e52853b6985e6bc62c' 
  AND token = 'JOp60hCqjPR3vkzqkvXQq+MrMD2Zw2NtNUzrIHcRomY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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