SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86f0c2d3a4b644bed5a73cd73da1103e68957ce6c97c1b7dd6f041f3864c382c' 
  AND token = 'bmJVMxFzsLILDA4ZPjKSgXbxRclZ5SbVPCWLwFUsvkc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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