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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd7e1817a30dc9a343918b29d993c5abeb520d9cb6f4d7fdefccb6c03fff77650' 
  AND token = 'P2x54AZQnzFPcHyRgfXS7lproEfzOgnW+XXDh7rL+nA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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