SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b48eaf1748ffc03d08b832e7090cfb27ee0b6595e1770a1ee704d45b697348a' 
  AND token = 'tXCYW7AMNFImo17RKiOjXKgPfCn9sc95zpyHzsc630E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00104

JSON explain

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