SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '611f05f14cb94908dfc13de51c851b5874f034f84e8cabebd22206732c846c65' 
  AND token = 'TOzTeCkNo7LZ223i6R3/J9WLS2j7XW83Q/W6yWfr7u0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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