SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '347365472e3b679560db42a1d1b5b2d99aa60114bd77fc7efac830c10930b7ef' 
  AND token = 'OQ/EUWKs+dfQvwF5D2ixQSiN7QRdhmrQDmY7uiuJdQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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