SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7a5a4116444783a81e0dfa33c73846ef56ce541a26c6b53335f3e47fef0b772' 
  AND token = 'H/+jEKlb5tqqnYg36r19QbvZU4LugZsmeZGzHJBBel4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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