SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f77bf8489fd8fd2423db9c0f81cbe502719e585b631bb309b6ee09664992296b' 
  AND token = 'cymcLpO1RKVTJHMZ3M0x279MGMZInbeVQjK8bwIXkFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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