SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a37305c17716ff654ff8fe2cfc4ea3ac45ab2ce3e5434519b44f9156a2cfdcd3' 
  AND token = 'rsn3Fn0KEaFUAE+1DjPHDWgJjWEYX0AG/X7Vh248uJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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