SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '578edbc3b0c8b99baaff7cefd37c7302adb135df1cfd77a38fb4c037aa75203a' 
  AND token = 'j6g5pz+d6ucOH5J6lpqp500uxek+XeRXPpKDE15fDL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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