SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d6f819b3a4897021828cf195bac72c045aac6efad2974ad4002b19a25f4c482' 
  AND token = 'grdQLU8fThrVBHJqZEND1yfamFYxLdZNTZYWSfgqqFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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