SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41b3e773de15be76aa11c544fff09c6116772c2d3382e3666fbd7b6dc9447af8' 
  AND token = 'hwTIw1Vvs+os9gnxSOjfG/Un8aBmuKrZRugw/m5h41o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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