SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b11704169ad9da690c03a1d72da69448630ffd6dbeb7490ef47efcc5291aaad' 
  AND token = 'T5gJDZwAnc3qKXSImVr+o6biQGhEsknsmDF4S38up3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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