SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6b506a44d4c592e7fc19ecd8a29abf60883215333d5618b566e4c7957e492a82' 
  AND token = 'tdF6QsZ/9PhWWE9PyNzWLp2dvwSECafxTgfnLV88mJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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