SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '797aba8d371b9cf79c339596f42d52aac18bbddacc08959adc016af0e1079c56' 
  AND token = 'K2/H7LBRomw+9uGKqXpsFUBJKH2OUNgdymn/hmuFvsw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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