SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '946974cebb05cafa1e1017c0096dc2635f433caaaf7cd809f560187586d09b52' 
  AND token = '2XO8sjpEi1Io2wQ6fjoEOVBp7mKA/1i4uFjbNrn5pPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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